Ice II

Ice II was discovered by Gustav Tammann in 1900 (Ref. 1). Ice II is proton-ordered and belongs to the $R{\overline {3}}$ space group, having 12 molecules per unit cell.

References

1. G. Tammann "Ueber die Grenzen des festen Zustandes IV", Annalen der Physik 2 pp. 1-31 (1900)
2. Barclay Kamb "Ice. II. A proton-ordered form of ice", Acta Crystallographica 17 pp. 1437-1449 (1964)
3. Barclay Kamb, Walter C. Hamilton, Sam J. LaPlaca and Anand Prakash "Ordered Proton Configuration in Ice II, from Single-Crystal Neutron Diffraction", Journal of Chemical Physics 55 pp. 1934-1945 (1971)
4. C. Lobban, J. L. Finney and W. F. Kuhs "The p–T dependency of the ice II crystal structure and the effect of helium inclusion", Journal of Chemical Physics 117 pp. 3928-3934 (2002)
5. G. Cruz León, S. Rodríguez Romo and V. Tchijov "Thermodynamics of high-pressure ice polymorphs: ice II", Journal of Physics and Chemistry of Solids 63 pp. 843-851 (2002)